Background: Biliopancreatic diversion (BPD) is the most effective bariatric procedure in terms of weight loss. However, analysis of the quality of life (QoL) has never been reported. The BAROS, giving a score to each operated patient on weight loss, improvement in medical conditions, QoL, complications and reoperations, has proven to be a standard reference for evaluating bariatric surgery outcomes. Methods: In order to apply the BAROS to BPD, we sent a questionnaire to 1,800 BPD patients who had been operated between 1984 and 1998.The responserate was 51.2%. Out of 1,709 questionnaires which actually reached their destination, we had 858 fully compiled returned. There were 615 women. 596 patients had had an ad hoc stomach (AHS) BPD, and 262 had had an ad hoc stomach ad hoc alimentary limb (AHS-AHAL) BPD. Results: According to the scoring key, 3.5% were classified as a failure, 11% were fair results, 22.8% good, 39.5% very good , and 23.2% excellent results. Considering AHS BPD and AHS-AHAL BPD separately,while the mean excess weight percent loss was 70.5±23 and 64.7±17 respectively, the failure rate was 6% in the first group and 2% in the AHAL group, while 11% and 6% of cases respectively were fair results, 24% and 20% good, 36% and 47% very good, 23% and 25% excellent results. Conclusion: The BAROS evaluation of BPD highlights the importance of its flexibility: the new policy of adapting the procedure to individual characteristics caused a drop in the failure rate and an increase in good, very good and excellent results.